Position a Halyard Attach point on your T-top pipe or Gunwale handrail without modifying your pipe or drilling holes in your boat! Easy Installation using our Flexible Gripping Clamp Design. Clamp flexes open to install around the pipe and grips the pipe when the fastener is installed. Three clamp sizes available (please specify pipe appropriate size when ordering). Contact us if you are not sure what size clamp you require and we will send you a pipe measuring template.